Continuous process for reacting turpentine and alkylphenols with phosphorus pentasulfide



June 2, 1970 F. c. GOLDSMITH 3,

CONTINUOUS PROCESS FOR REACTING TURPENTINE AND ALKYLPHENOLS WITH PHOSPHORUS PEN'IASULFIDE Original Filed Oct. 23, 1961 INVENTOR FRED C GOLDSMITH ATTORNEY United States Patent US. Cl. 260139 3 Claims ABSTRACT OF THE DISCLOSURE Reactions of solids with liquids, wherein the product is a liquid, are carried out under continuous conditions by circulating a slurry of the solid reagent, a major of the liquid phase of the slurry being inert to the reaction (that is, being either product or solvent), in a closed system and adding the liquid reagent while maintaining an excess of the solid reagent. The liquid product is drawn off at about its rate of formation. The method is particularly applicable to the reaction of phosphorus pentasulfide with phenols or turpentine.

This application is a division of copending application Ser. No. 132,316, filed Oct. 23, 1961 now US. Pat. 3,335,158, which is a continuation-in-part of application Ser. No. 680,882, filed Aug. 28, 1957, now U.S. Pat. 3.086,849. The latter is a division of application Ser. No. 262,600, filed Dec. 20, 1951, now US. Pat. 2,862,947.

This invention relates to a novel process for reacting a plurality of reagents, at least one of which is a liquid and at least one of which is a solid. More particularly, it relates to a method of reacting solid and liquid reagents to form a liquid product which includes the steps of continuously circulating in a closed system a slurry of at least one solid reagent, the major portion of the liquid phase of said slurry being inert to the desired reaction, introducing into said closed system at least one liquid reagent at rates so as to maintain said solid reagent at every point in said system in amounts greatly in excess of the minimum amounts required for complete reaction with the amount of liquid reagent present at that point, maintaining the temperature of the continuouslyv circulating stream of slurry for a substantial portion of its circulating cycle at a temperature favorable to the desired reaction, and drawing 01f from the system liquid product at about its rate of formation.

A principal object of this invention is to provide a proc ess by which reactions of the character defined may be carried out expeditiously, at low cost, and by the use of simple equipment which may be readily controlled.

Other objects of the invention will appear as the description proceeds.

By the present invention, the reaction is carried out with the reagents in the form of a slurry which is continuously circulated. By continuous or intermittent re plenishment of the reagents taken up by the reaction and preferably also by the continuous or intermittent withdrawal of the products formed, the process may be made fully continuous.

The method of this invention is adapted for use with both endothermic and exothermic reactions since it is relatively easy to effect the necessary temperature control as by heating or cooling of the reaction mass as it is circulated. The invention is particularly adapted for use in reactions wherein the reagents have measurable differences in specific gravity and especially in connection with reactions which permit the presence in the reaction mass of substantial excesses of one of the reagents, since by maintaining those conditions it has been found possible to control the rate of replenishment of the reagents by such simple means as density responsive equipment.

More particularly, the invention is applicable to reactions such as those in which a solid such as phosphorus sulfide is reacted with an organic hydroxy compound such as an alcohol, phenol, or naphthol in the production of phosphorodithioic acids. The invention is applicable also to the preparation of metal salts of organic acids such as phosphorodithioic acids and sulfonic acids.

Referring now to the preferred form of the invention shown in the drawing, slurry 1, comprising solid reagents such as a phosphorus sulfide suspended in a mixture of a small proportion of liquid reagent such as an alkylated hydroxyaromatic compound and a relatively large pro portion of a diluent, which can be an inert material or preferably the liquid product of the reaction of the solid reagent with the liquid reagent, is maintained at a uniform temperature in reactor 2. The solid reagents form the solid phase and the diluent the liquid phase of the slurry is agitated in the kettle by stirrer 3 and vanes 7 attached to the wall of the kettle. The powdered solid reagent is loaded into feed hopper 4 located above reactor 2. The solid reagent is continuously fed into the reactor 2 from hopper 4 by means of a revolving vertical screw 5 extending into the top of the reactor. The screw 5 fits the barrel 6 of the hopper 4 closely and provides gas-tight seal between hopper 4 and kettle 2. The liquid reagent is continuously fed into the slurry by line 8 connected to line 9, or if desired by a line connected into the top of reactor 2. The liquid reagent and solid reagent react in reactor 2, forming a liquid product and liberating a gas. A vertical weir 10 is provided in reactor 2. A baflle 11 is spaced from weir 10 and provides a quiescent zone around the weir 10. A portion of the slurry in the reactor overflows continuously weir 10 and flows doWnline 20 into solids separator 12 located below the reactor. The decanted liquid phase of the slurry, essentially free of solid reagent, overflows the side of separator 12, into the receiver 13. The solid reagent enriched separator slurry stream is fed to a pump 14 and returned to the reactor 2 by line 9. The liquid phase of the slurry is pumped from the receiver 13 by pump 22 to a suitable storage tanks, not shown. It the diluent is a material other than the reaction product of the solid and liquid reagents, further steps will have to be taken to separate the diluent and product. For this purpose a flash evaporator 60 can be employed to evaporate the diluent and conduct the diluent vapor by line 61 to cooler 18 where the diluent is condensed and returned to the slurry by line 19. Thus, it is desirable for most purposes to use where possible the reaction prodnot as the diluent.

The by-product gas atmospheres in the reactor 2, separator 12, and receiver 13 are collected in lines 14A, 15, 16, respectively, connected to common line 17. The byproduct gas liberated is normally saturated with evaporated liquid reagent. The gas stream is passed by common line 17 to gas cooler 18, and the liquid reagent condensate is run back into reactor 2 by line 19. The cooled gas then passes to an absorber by line 21, not shown, or is disposed of in some other way.

The specific gravity of the solid reagent is substantially different from the liquid from the liquid phase of the slurry so that, as the concentration of solid reagent in the slurry increases, the density increases; and as the concentration of solid reagent in the slurry decreases, the density decreases. Thus, the measured density provides a means for controlling the feed ratios of the reagents. The liquid reagent feed may be kept constant and the solid reagent feed varied, or the solid reagent feed may be held cona stant and the liquid reagent feed varied. The first method is used in this unit, but the latter method may be used equally well.

The solid reagent should have a specific gravity that is substantially different from the liquid phase of the slurry. In the process and apparatus of this invention it is desirable to employ a solid reagent with a specific gravity substantially greater than the specific gravity of the liquid phase of the slurry.

The solid reagent employed should be in a finely divided state, and it is preferable to use a solid reagent which will pass through. No. 20 U.S. Standard Screen.

In the preparation of phosphorus thioic acids the solid reagent can be a phosphorus sulfide, for example:

maintained at every point in the system in amounts greatly. in excess of the minimum amounts required for complete reaction with the alcohol present at that point. Thus, the alcohol when introduced into the slurry reacts almost immediately with the P 5 to insure accurate control of the rates of feed by the densometer. The organo phosphorodithioic acid is decanted essentially free of P 5 from separator 12 to receiver 13. It has been found that it is equally satisfactory to vary the alcohol feed rate while maintaining constant the P S feed rate.

Phosphorus disulfide-P S (PS 15 phosphorus triSu1fide P4S6(P2S3) While the above data relate to the reaction of phos-' phosphorus sesquisulfide p4sa phorus pentasulfide and alcohols, the process is appliphosphorus pentaSu1fid6 P2S5(P4Sm) cable also to the reaction of phosphorus sulfides and phosphorus heptaSu1fide P4S7 ilgdll'oxghonlatlc tiompounds sturh bas phenolsl Iand 1133p}?- o s. 1s 1s ra er unexpece ecause, at oug t e 53 p g fiu rggzz 2 55:5321; gtz z W111 be chemistry of the reaction of phenolic compounds with phosphorus pentasulfide 1s analogous to the chemistry of The llquld reagent, 1!! Such a Preparatlon, y be an the reaction of alcohols with phosphorus entasulfide the alkylated hydroxyaromatic co p d, all alkylated engineering features of the two reaction are obvidusl Phfillolic compound- Thus y an alkylated Phenol quite dissimilar. Alcohols differ markedly from phenoli c or an alkylated naphthol; 1ll11strat1ve examples include compounds t l as t their physical properties, viz, butyl phenol, octyl phenol, dodecyl phenol, oct y alcohols generally are liquids whereas phenolic comphenol, a-hexyl p-naphthol, p-decyl ot-naphthOl, a-eic y pounds are for the most part solids but also in their fi-llllalihgiol, iand bpolyisolgutyl-substituted ot-naphthol in relative chemical activities w 1c e po y1so uty su stituent is derived from a 01 isobutene having an average molecular weight of 1 300 6. t s this mvFntloll i f to be Satlsfa?" If the alkylated hydroxyaromatic compound is a solid on y Opera 6 Teactlons mvo vmg ydroxyaicmatlc it can be dissolved in an inert solvent and in that manner compound? partlculafly alkylated hydroxyaromatlc be employed as a liquid reagent in the process. Phosphorus sulfides gellerany' The liquid reagent may also be an alcohol, for example AS mdlcia'ted f prepafatlon of metal i s 9 a monohydric or dihydric alcohol. The following table the aromatic and aliphatic substituted PhOSPlIOIOdlthlOlC summarizes typical operating conditions in the process aclds may be efiected the Same manner and m the and apparatus described above for the preparation of Same apparatus as the acids- Likewise, metal Salts of phosphorodithioic acids by the reaction of P 8 and variother organic acids, s, metal sulfonates, can be p ous alcohols. 40 pared in this fashion. In such cases the solid reagent is TYPE OF ALCOHOL Methybl-iioi 1 Item Condition carb i n l ISO a l li Blend 1 .A Alcohol feed rate, lbs/hr 472 277 700 B P285 feed rate, lbs/hr 244 244 293 o Acid rate, lbs.,'hr..- e19 483 94s I)... HzS rate, lbs.lhr 37 38 E Operating tomp., 2 170 210 1. 0404. gag 0 918-0. 936

10 Operating density... 0. 955-0.

- Percent P28 in slurry 1 Blend-37.5% n-octyl alcohol, 37.5% methyl-iso-butyl earblnol, 25% n-hexyl alcohol.

To persons skilled in the art, a description of the operation of the process and apparatus constituting the present invention will be found useful. In the preparation of phosphorodithioic acids by the reaction of P 8 and alcohols or alkylated hydroxyaromatic compounds, the reaction is illustrated by the following equation:

180/ \SH The liquid phosphorodithioic acid is preferred as the diluent in this process. The alcohol is fed into reactor 2 heated to reaction temperature (see item B in the table above) after the alcohol overflows weir 10, the alcohol is shut oif. The P 8 feed is begun (see item B in the table above), and as the density approaches the desired range (see item F above) the alcohol feed is begun at one-half the normal feed rate (see item A above). Over a four hour period the alcohol feed rate is gradually increased to normal. The slurry, comprising essentially phosphorodithioic acid and P 8 is continuously circulated from reactor 2, over weir 10, to separator 12, and then P285 4R-OH --2 His a basic inorganic compound and the liquid reagentlis 5 a phosphorodithioic or sulfonic acid.

Suitable metal salts include those of metals in Groups I, II and HI of the Periodic Table and especially the alkali metals, alkaline earth metals, and zinc.

An illustrative preparation of zinc phosphorodithioate by this process is a preparation of the zinc ,salttof a phosphorodithioic acid prepared in turn by the reaction of four moles of a 65:35 molar mixture of isobutyl and primary amyl alcohols with 1.0 mole of P s The solid.

oxide; the liquid reagent is a solution of 22. percent by weight of petroleum sulfonic acid in 25 percent of isopropyl alcohol, and 50.5 percent of mineral oil (2.5 percent of sodium petroleum sulfonate being present as an impurity). The temperature of the reaction in this example is 135140 F.

The above examples illustrates the wide applicability of the process of this invention and it is thus apparent that the process can readily be adapted to the preparation of such metal salts as calcium sulfonates, barium sulfonates, magnesium sulfonates, sodium sulfonates, calcium phosphorodithioate, barium phosphorodithioates, potassium phosphorodithioates, etc.

Illustrative examples of pairs of liquid reagents and solid reagents which are reacted advantageously according to the process of this invention are shown below.

'Polybutene of about 750 molecular weight.

What is claimed is: 1. In the process of reacting phosphorus pentasulfide with a liquid reagent selected from the group consisting of alkyl phenols and turpentine to form a liquid product, the steps of continuously circulating in a closed system a slurry of said phosphorus pentasulfide, a major proportion of the liquid phase of said slurry being inert to the reaction, introducing into said closed system said phosphorus pentasulfide and said liquid reagent at rates so as to maintain said phosphorus pentasulfide at every point in said system in amounts greatly in excess of the minimum amount required for complete reaction with the amount of said liquid reagent present at that point, maintaining the temperature of the continuously circulating stream of said slurry for a substantial portion of a circulating cycle and drawing off from the system the liquid product at about its rate of formation.

2. The method of claim 1 wherein the liquid reagent is an alkyl phenol.

3. The method of claim 1 wherein the liquid reagent is turpentine.

References Cited UNITED STATES PATENTS 2,356,073 8/1944 May 260-139 2,665,295 l/ 1954 Augustine 260958 2,862,947 12/1958 Goldsmith 260981 CHARLES B. PARKER, Primary Examiner A. HtSUTTO, Assistant Examiner U.S. Cl. X.R. 

